Fire control apparatus



S. G. GERDIN FIRE CONTROL APPARATUS Sept. 11, 1961 Filed Feb. 26, 1947 3Sheets-Sheet 1 &

.TNYENTOR 5w Gamma 651mm lr'romvs y ep 1 s. G. GERDIN 2,567,665

FIRE CONTROL APPARATUS Filed Feb. 26, 1947 3 Sheets-Sheet 2 I/v VEN ranI VEN 601mm? GERb/N BY L ch-4 2- H P 1, 1951 s. G. GERDIN 2,567,665

FIRE CONTROL APPARATUS Filed Feb. 26. 1947 3 Sheets-Sheet 5 74 All Y .mvz/vrole .fmw Gum/4R 651mm Patented Sept. 11, 1951 FIRE CONTROLAPPARATUS- Sven Gunnar Gel-din, Bofors, Sweden, assignor to AktiebolagetBofors, Bofors, Sweden, a corporation of Sweden Application February 26,1947, Serial No. 731,109 In Sweden December 31, 1943 6 Claims. 1

This invention relates to target tracking devices for fire directioninstruments, particularly to devices for determining the lead point forthe shelling of targets moving in space.

One of the objects of the invention is a novel device of the generaltype, above referred to, in which the coordinates of the target and itsvariable speeds are measured in one spherical coordinate system, and theaiming device is combined with elements representing the coordinatesmeasured and the speed variations in coordinate systems difierent atleast in part from the first mentioned.

Another, more specific object of the invention is a novel device of thegeneral type, above referred to, in which the aforementioned elementsare arranged so that the measured target speeds, are shown by means of aspeed or a speed component within a plane representing the plane ofsight. The representation of the speed, respectively thespeed-components are given on a scale inversely proportional to themeasuring distance. The representative elements are arranged andconnected with the adjustment instruments of the sighting mechanism insuch manner that the point in space, defined by the representativeelements, and representing the observed present position of the targetor target point, receives automatically a velocity fixed with regard tomagnitude and direction, and controlled by manual adjustment of suitableadjusting elements. This velocity corresponds always to a target pointmotion uniform with regard to size and direction and traveling along apath determined by the point position.

Another object of the invention is a novel device of the general type,above referred to, in which the elements for the manual adjustment ofthe speed of the representative point in space are arranged so that eachone of them controls the elements for the speed variations of thecoordinates of the representative coordinate system in such mutualrelationship, that in the coordinate system of the aiming device onlythe speed variation corresponding to the actuated adjusting elementexperiences a change.

Other and further objects, features and advantages of the invention willbe hereinafter set forth and the novel features thereof defined by theappended claims forming part of the application.

In the accompanying drawings a now preferred embodiment of the inventionis shown by way of illustration and not be way of limitation.

In the drawings:

Figs. 1 and 2 show diagrams of certain relationships in the lead pointdetermination.

Fig. 3 is a diagram in the plane of sighting.

Fig. 4 is a diagram in a plane perpendicularly to the line of sighting.

Fig. 5 shows diagrammatically an embodiment according to the invention.

Fig. 6 shows part of Fig. 5 in detail, and

Fig. 7 is a computation diagram.

The characters as used in Fig. 1 represent:

I-instrument point (location at which the instrument is set up) IO-fixedhorizontal or azimuth direction M-target point at moment of measuringIMsight-line (sight line from the instrument to the target pointN-projection of M upon the horizontal plane through I T-lead pointIT-line of sight of lead point (line of sight from the instrument tolead point T) MIT-planeplane of trajectory sight (the plane whichincludes IM, the targe course and IT v-velocity of the target pointMR-horizontal straight line, perpendicularly to MS--straight line,perpendicularly to IM and located in MIT-plane IF-rotating azimuth axisof the instrument IGhorizontal line, vertical to IM, forming theelevation axis for the telescopic sights of the instrument Z-targetpoint distance IM a-angle OIN=defiection angle of target point 40 in thehorizontal plane angle MIN=elevation angle of target point x K-angle RMSvangleSMT It is known that a lead point determination can be made bymeans of the values as per diagram of Fig. 2, which is a reproduction ofFig.

I 1, except that each distance is represented at a scale proportional to3 The points I1, M1, etc. in Fig. 2 correspond to the points I, M, etc.in Fig. 1. Such a leadpoint determination requires familiarity with, forexample, the values of the angles a and s resp. K and 1', whichcharacterize the position and speed, of the target, of the relativetarget speed as well as the midpoint distance I or a simple function ofit. Instead of the values 11 and e, the components 11' and A as shown inFig. 3 may also be chosen.

The device according to the invention determines automatically thevalues for the telescopic sight and range finder when used for targettracking. Also the device causes the speed variations for the adjustmentangle of the telescopic sights and the range adjustment of the rangefinder instrument to vary automaticallyonce the device has beencorrectly set with regard to the coordinates of the target and theirspeed variationsso that the telescopic sights and the range finderinstrument remain set on the target if it continues its course along astraight path and with a uniform motion. It is known that such a linearautomatic tracking of the target with telescope and range finder ispracticable in such a way, that the coordinates and the velocity of thetarget point are represented as coordinates and speed components in anappropriate coordinate system. The latter permits a certain speed to beimparted by manual adjustment to the point fixed by the representativecoordinates. The speed is then kept unchanged with regard to magnitudeand direction during the displacement of the point, until one of theadjusters makes a new manipulation. The elements representing thecoordinates and speed components in the second coordinate system, areconnected with the elements for the aiming of the telescopes and theadjustment of the range finder in such a way, that the point in space,defined by the adjustment of these devices, moves automatically at auniform motion with regard to magnitude and direction. Thus, once thesighting mechanism has been correctly set, it tracks the targetautomatically, without necessitating any readjustment of the speedvariations of the successive values supervised by the adjusters. Hence,the adjusters need to make adjustments only when a setting error occursor the target course or speed is changing.

With the devices for automatic tracking, as hitherto known, it is alwaysnecessary that the representing coordinate system constitutes areproduction on a fixed scale of the conditions in space.

According to the invention it is possible to arrange the elements forthe representative coordinates so that the speed of the target point isrepresented on a scale inversely proportional to the distance of thetarget point. Whence the representative speed maintains a uniformdirection, and in respect to its magnitude it obtains such a motionvariation, that the elements representing this velocity direct theelements for the adjustment of the telescopic sight and the range finderin such a way, that the point in space, fixed through the adjustment ofthese elements, obtains a uniform motion with regard to magnitude anddirection.

Further, the invention makes it possible that the representative motionconsists of components, which represent the components of the 4 targetpoint velocity contained in the plane of the trajectory sight. In aspecial case the resultant of the target point motion is shown.

Fig. 3 shows the plane of the trajectory sight relating to Fig. 2, butwith the distances and angles contained therein. The designations are inpart the same as in Fig. 2. In addition:

IAthe vertical to the target course MT MB-the vertical to the line ofsight IM v=AAIM=ABMT v=izl ariable speed of these angles A: (speedvariation of the distance divided by l the distance) The followingrelationship results from Fig. 3:

A =e. sin y l v'=6'. cos v For the value the following variable speed e"results:

e,, lv'v.l' l: 2

since 11 is zero, as the target is assumed to move with a constantvelocity. The angular velocity vector 11, which lies in a plane verticalto the line of sight IM, may be divided into a velocity vector of theangle of elevation (p', and a velocity vector of the angle of deviation0'', as seen on Fig. 4 which shows this plane. The characters of Fig. 4agree with those used in Figs. 2 and 3.

The operation of the device, as shown in Fig. 5 is based, among others,upon the relationship as given by Equations 1 to 4.

According to the embodiment shown in Fig. 5, a fiat disk I is rotatedwith a uniform velocity by a speed regulated motor. Engaging disk I is afriction wheel 2, which is radially movable towards disk I, by means ofclawlike elements 3 and a nut 7 displaceable on a screw 8. The frictionwheel 2 is rotated with a velocity, which is proportional to itsdistance from the centerpoint of the disk I. This distance may beproportional to E, so that the rotary velocity of the Wheel 2 isproportional to E. This rotary velocity is transmitted by an axle 4 to acomponent resolving apparatus 5. This latter is arranged in such a way,that a rotary velocity in imparted to it, is divided into two rotaryvelocities no and nm at axles 9 and I0 respectively according to thefollowing equations:

n =n sin n where u is an angle set up in the apparatus 5, whose valuecan be determined by means of an axle 6. Giving it a value v, acomparison be-- tween Equations 1 and 5 shows that Hence, axle 9receives a rotary velocity, which is proportional to A. The position ofits angle becomes proportional to Coupled with this axle shall be therange-finder. The axle l0 receives an angular velocity proportional to11'. By transmitting this rotary velocity with a suitable ratio oftransmission to the angle adjusting element of apparatus 5, angle u iscaused, after having been given the correct starting value as describedbelow, to follow automatically the value v, if the latter varies duringthe tracking of the target. The rotary velocity of axle l0, proportionalto v, is transmitted to axle 6 through bevel gears ll, l2 and I3, l4, anaxle [5, a differential I6, an axle l1, bevel gears I8, l9, an axle 20,bevel gears 2|, 22, an axle 23, and bevel gears 24, 25. The rotation ofaxle I0 is further transmitted to an apparatus 26, which is similar toapparatus 5. The angle u receives the value K in apparatus 26 throughaxle 21, and this latter transmits to the axles 28 and 29, the rotaryvelocities n28 resp. me, which are proportional to (p' resp. 0 accordingto a comparison betweenEquations 3 and 5. The rotary velocity of theaxle 28 is transmitted through suitable step-down gears to the axle ofelevation of the telescopic sight. The rotation of axle 29 istransmitted to a resolving apparatus 33, which is arranged in such away, that for a given rotational velocity m9 of axle 29, it transmits tothe axles 3| and 32 the rotational speeds 1m resp. 1232' in accordancewith equations:

7332 7229 tan '14 The value (p is given to the angle 11. in apparatus 30by means of bevel gears wheels 33, 34, an axle 35, bevel gears 36, 3 1and an axle 38. Comparing Equations 4, 4a and 6, shows the followingresults:

The rotational velocity of axle 3| is transmitted to the azimuth aimingdevice of the telescopic sight by means of a step down gearing. The usewhich is made of the rotational velocity of the axis 32 is describedhereinafter.

A disk 39 serves to obtain automatically the value 6' i. e. for theformation of e". The disk 39 receives a rotational velocity proportionalA from axle 9 by means of bevel gears 40, 4|, an axle 42 and bevel gears43, 44. Engaging disk 39 is a friction wheel 45, which is displaced byclawlike element 46 so that the distance of the wheel 45 from the centerof the disk 39 remains always equivalent to the distance of the wheel 2from the center of disk I. This distance is proportional to c. Therotational velocity of wheel 45 becomes proportional to the rotationalvelocity of disk 39 and the distance of wheel 45 from the center of thedisk 39, i. e. to the product e'Jt. A comparison with Equation 2 showsthat this is proportional to e". The rotational velocity of the wheel 45is transmitted through an axle 41, a differential 48 and bevel gears 49,50 to screw 8. Through rotation of the latter, the value of c isinfluenced in such a way, that 6' becomes smaller when A and e arepositive. The angular position of the axle 41 is additive indifferential 48 6 so that a desired starting value of a can be set byrotation of axle 41.

In order to track a target, an observer adjusts in his telescopic sightthe azimuth hairlines to the position and velocity of the target.Another observer adjusts in his telescopic sight the elevation hairlinesto the position and speed of the target. A third observer ascertainsthat range and range rate as set in a range finder instrument coincidewith those of the target. If one of the three observers notices adiscrepancy in the target tracking as to the value observed by him, hemakes in the device described above such combination of changes of e', vand K, that for the respective value controlled by him correctadjustment is restored. However, it is practically impossible for therespective observers, to judge for each occurring situation thatappropriate combination of changes to be made, and at the same time toexecute the same. Hence, the device for target tracking must be arrangedin such a way, that each observer has a handwheel which directs theelements for the adjustment of e, v and K in such a way, that of thevalues indicated by the tracking device only the value watched by thisparticular adjuster is influenced. The pertinent arrangements are shownon Fig. 5. The conditions for the operation of these arrangements can bededuced from Equations 1, 3 and 4a. In (1) the first equation ismultiplied by sin 1 and the second by cos 1 whereupon the results areadded. Thus one obtains:

A change As of a due to small changes of 7v and v is then given byAe'=A)\' sin V-I-Av' cos p 7 Similarly there is obtained from (3)A'U'=A(p' sin K+A r' cos K 8 and from (4a) Ao"=Aa. 005 q) Division ofthe Equations 1 results in A change A1) of 'v determined through smallchanges of A and 11 is then given by Av v'A \)\Av' cos 1/ v 2 or byentering the relations of Equation 1 by The relations obtained may bereduced to the following equations:

A:p.cos K-Aa. cos (F-SiD K AA .sin v-i-Ag'.sin .003 v-i-Aa' cos p.008x.cos r 14 The Equation 12 is derived from 11a and 9. the Equation 13from 7, 8 and 9, and the Equation 14 from 10, 8 and 9. From theEquations 12, 13 and 14 it is immediately apparent that a change Ad istransmitted to the elements for the change of angle K in the ratio cosc. sin I:

e cos y as well as to the elements for the change of angle in the ratiocos 0.00s u.si'n v and to the elements for the change of e in the ratiocos (p cos K cos 1/. Further it is apparent that a change of Ag) istransmitted to the elements for the change of angle 1: in the ratio COSx 6' cos v sin x sin v and to the elements for the change of e in theratio sin K.cos v. The final result is that a change AA is transmittedto the elements for the change of v in the ratio cos c I and to theelments for the change of e" in the ratio sin y.

In order to secure automatic tracking, devices are required which impartto the set values e, v and K, automatically the correct speedvariations. Devices for the correct variation of e and v are previouslydescribed. The variable speed of K may be computed by means of Fig. 7.In this figure, points I1, M1, N1 and O1 correspond to the points ofsame designation in Fig. 2. 01 represents in this figure at the sametime the point of intersection of the target course with the horizontalplane (the fixed direction I101 has been selected in this manner). M1Klies in the plane of sighting I1O1M1 and is vertical to I1M1; that is,the vector 1) runs along M1K. The line I1N1 is extended to the point L,which latter is located so that LM1I1 is a right angle. As KM1I1 andLM1I1 are right angles, the plane KLM1 is vertical to the line I1M1. Theangle 1: lies hence in the plane KLM1. 1: is the angle between KM1 and ahorizontal line M1R1 vertical to I1M1 through M1. Line M1R1 lies hencealso in the plane IQMi. In this plane, KL is horizontal and henceparallel to line M1R1. The angle LKM1, is hence equal to K. As the planeM1LI1 is a vertical plane, the horizontal and to I1M1 vertical line M1R1is vertical to every line in the plane M1LI1. Hence, this is also truefor the line KL, and the angle KLI1 is therefore a right angle. Settingthe length of M1I1=1, the following applies:

LM =tan go tan :1

cos o tan cos =Z$ Z 15 Setting angle and angle and drawing N1H verticalto 0111, one obtains N1H=M1N10t cp.Sin a=M1N1.cot 1 .5111 5 and fromthis sin a sin 3 Solving (P, in (17) and introducing the value for 1:one obtains =m.S1l1lp.d=-Sl[l 99.6! 18 According to Equation '18 thespeed variation of K is represented in Fig. 5 as a rotational velocityof axle 32 proportional to a sin (p.

The relationship obtained from the various variable velocities may bereduced to the following expressions:

, e.cos u.cos K COS go K: e.cos v.cos man go Of these, the first resultsfrom (3) and (4, the second from (3) and (1), the fourth from (18). (3)and (4), and the last from (1). As wheel 2 and the axle 4 represent thevalue 1: through their angular velocities, the conditions representedthrough Equations 19 for the automatic target tracking with the deviceaccording to Fig. 5 can be summed in such a way, that the axle l is insuch gear connection with a plurality of other elements, that theseelements represent certain speed variations by means of their angularvelocities. The angular velocity of axle 4 must therefore be transmittedat a ratio of COS V COSK to the element 3| for the representation of thespeed variation a and at a ratio of cos .sin x to the element 28 for therepresentation of the speed variation and at the ratio sin y to theelements 9, 42, and 39 for the representation of the variation speed A,and at the ratio 01 --cos 1 .cos 1: .tan to the element 89 for therepresentation of speed variation 1:, and finally at 9 the ratio of cosv to the elements I and I for the representation of the speed variation12. All these conditions are fullfilled with the device according toFig. 5.

Fig. 5 shows also the devices, which form automatically the incrementsAe', A11 and AK of the values 6', 11 and K from the increments: Aa', A92and All to the adjustment speeds added by the adjusters of the targettracking instrument. The handwheel for the azimuth observer for theadjustment of the azimuth tracking velocity is designated by 5|. Bymeans of this wheel 5|, a resolving apparatus 52 receives increments tothe rotational angle proportional to Ad. The apparatus 52 is arranged insuch a way that when receiving a rotational angle Aw51 it turns the axle53 through the angle A1053. This latter has the following relation toangle L053 Aw53=Aw51.cos u 20 By means of bevel gears 33, 34, axle 35,bevel gears 54, 55, and an axle 56, there is received the value 0 in theapparatus 52, and N053 becomes proportional to All. COS (p=Aa" The angleincrement mentioned is transmitted to an apparatus 51.

By means of a handwheel 58, the adjuster for elevation transmits angleincrements to an axle 59, which are proportional to the angular veloc--ity increments A a desired by the adjuster for elevation. These angleincrements are also transmitted to an apparatus 57. This apparatus 51,shown in Fig. 6 more in detail, includes two similar component formingdevices, one coacting with axle 53 and the other with axle 59. Each ofthese devices comprises a spherical ball H6 and I2I respectively whichby means of supporting rollers (not shown) is mounted freely rotatablyabout its own center. The balls are revolved by means of a drivingroller l I 5 and I20 respectively which rollers are mechanically coupledto the corresponding one of the axles 53 and 59 so as to follow therotation of the respective axle. The mounting axis of each of saiddriving rollers is so connected to a rotatable element, for instance arotatable ring I23 and I24 respectively, that the mounting axis by meansof said element can be set in a position in which it forms an angle a ofany desired value with a fixed direction. In Fig. 6 each of saidrotatable elements is set to the desired angle by means of a drivingroller H1 and I22 respectively, driven by an axle 62. Each of the ballsis engaged by two rollers H3, H4 and H8, H9 respectively which rollersare driven by the balls and so mounted that the mounting axis of one ofthe driven rollers of each pair is parallel to the aforesaid fixeddirection while the mounting axis of the other driven roller of the pairforms an angle of 90 degrees with the said direction. By this means, arotation of, say the axle '53, through a certain angle A1053 willproduce rotation of one of the corresponding driven rollers through anangle Aw53.COS u and rotation of the associated driven roller through anangle Awaasin u in one or the other direction as desired. The rotationsof the driven rollers are transmitted by means of their axles H2, H0 andIII, I09 respectively to two difierential gearings I01 and I08respectively, included in the apparatus 51. One of these differentialgearings drives an axle 60 and the other an axle 6|. The connections arso selected that the angle increments Awe and A2051 of said axles 60 and6| respectively resulting from the angle increments Awss and Awss of theaxle 53 and 59 respectively, at any value of the said angle 11. willfulfill the following equations:

Aww=Aw sin u+ A10 cos it 21 Aw =Aw cos uAw sin u The two rotatableelements in which the drive rollers are mounted are mechanically coupledto an axle 62 by means of which the angle u can be given the value K.From Equation 8, it is apparent that A'wco becomes proportional to Al)and from Equation 11a, that Awm becomes proportional to Axe-cos 11.Similarly, an apparatus 63 of the same structural design as apparatus 51forms from the angle increments transmitted through the axles 64 and 65,which increments are proportional to An and also to the increments ofthe speed variations M of the logarithm of the distance as introduced bya wheel I6 by the person measuring the range, angle increments of theaxle 41a and 11, which according to Equations 7 and 10 are proportionalto the following The angle increments Aweo of axle are transmitted toaxle 64 through the bevel gears 66, 61 and 68, 69, an axle I0, bevelgears II, I2, an axle I3 and bevel gears I4, I5. The increments to ereceived through the axle 41a are transmitted through differential 48 toscrew 8, which determines the position of friction wheel 2. Intodifferential 48 the continuous automatic increment to e is introduced byfriction wheel 45.

A continuously variable gearing I8 is adjusted by means of an axle I9.The adjustment of the latter is controlled through the position of thescrew 8 which is adjusted for the gear ratio by bevel gears 80, 8|, andaxle 82 and bevel gears 83, 84.

According to Equation 10, this gearing forms angle increments to an axle85 proportional to the angle increments A introduced by means of axleI1. In differential I6, the angle increment of axle proportional to A11is added in the proper proportions to the rotational angle of axle I5,which changes proportionally to the angular velocity 0'. Thus therotational angle of the axle II receives a proper startin value due tothe increments of the training velocity entered by the observers intothe target tracker by the hand wheels 5|, 58 and I6. The rotationalangle of axle I I also receives a proper variable speed due to therotational velocity of axle I5, so that the rotational angle mentioned,continues to adhere to its proper value. Hence, the angle of setting uin the apparatus 5 and 63 receives at all times the proper value v.

A ballastic cam 8! is located in the carriage 86, which latter moves inthe same relation as friction wheel 2, that is, so that the displacementdistance is proportional to e. The cam 81 rotates through an angleproportional to angle 11, about an axis parallel to the direction of thedisplacement of carriage 86. This rotation occurs by means of axle 23,bevel gears 88, 89, an axle 90, a cylindrical gear 9|, and a cogwheel92, which is fixed to cam 81. The cam is formed so that a feeler dog 93resting against its surface is displaced from its original position by adistance, constantly proportional to the momentary value of 6' cos 1/. Afollow-up motor 94 is arranged in such a manner that it constantlyimparts to an axle 95 a rotational angle, which is proportional to thedisplacement of dog 93, that is proportional to c"COS 1 when measuredfrom a fixed original position. A gearing 96 is adjusted by means ofaxle 95, hence corresponding to 6' cos v. This gearing is designed insuch a manner, that its gear-ratio becomes proportional to 1 ecosv Inthe gearing 96, the angle increments Awfil are transmitted to axle 6|.Due to this gear-ratio, the angle increments of an axle 9'! becomeproportional to AK, as apparent from Equations 11a and 21. In adifferential 98, these angle increments are added in the correctproportion to the angle position of axle 32, which changes proportionalto the angular velocity (0."Slll (p). As the azimuth and quadrant orelevational sight adjusters turn the respective Wheels, an axle 99receives the proper starting angle. The latter maintains its correctvalueproportional to KV-due to the automatically correct rotationalvelocity of axle 32.nThe angular position of axle 95 is transmitted toaxle 62, by means of bevel gears I00, [DI and further to axle 2'! bybevel gears I02, I03, an axle I04 and bevel gears I05, N16. The angulardisplacements u of apparatus 51 and 26 automatically maintain itscorrect value throughout.

This description pertains only to one now preferred embodiment offtheinvention. The latter may also be accomplished by representing, by meansof appropriate elements, for example the velocity components 7V and 1:shown in Fig. 3. In that case, additional elements have to beintroduced, Whichtransrnit automatically to A and v the proper variablevelocities x resp. 12'.

These may be computed from Equation 1. A derivation results in: 7

\"=e .sin v+e.cos vLv a 22 v=e"*. cos v-e sin v.11

Introducing 5" according to Equations 2 and a sin resp. cos 1 accordingto Equation 1, results in: I 7

V xll vl 2 2 W 23 v"=-2.v'.

v and A may be formed analogous to e in the embodimentpreviously'described, and o x 2 and v,7\' may be formed analogous tos"7\' as describedabove.

For the shelling of moving targets, a target tracking device accordingto the invention permits to ascertain all data, as are needed for thedetermination of the lead point. These data are conveyed to a computinginstrument especially devised for this kind of determination. Forexample: In the embodiment of Fig. 5, the magnitude of a may be learnedfrom axle 3|, the magnitude of 17) from axle 28, the magnitude of A fromaxle 9, the magnitude of I: from axle 99, the magnitude of o from axle20, and the magnitude of E from axle 8.

While the invention has been described in detail with respect to acertain now preferred example and embodiment of the invention it will beunderstood by those skilled in the art after understanding theinvention, that various changes and. modifications may be made Withoutdeparting from the spirit and scope of the invention and it is intendedtherefore, to cover allsuch changes and modifications in the appendedclaims. W

What is claimed as new and desired to be secured by Letters Patent is:

1. In an automatic target tracking apparatus for targets moving throughspace, the combination of a first group of means comprising a shaftsystem including an azimuth shaft 3| for registering the present azimuthangle (a), a shaft 28 for registering the present elevation angle and ashaft 9 for registering the present range value (loge= the valuesregistered by said shafts, respectively, representing in polarcoordinates the position of an observed point (M) in space. a variablespeed mechanism l, 2 for rotatin the said shafts, continuously variablere solvers 5, 26, 30 interconnecting the said shafts with said speedmechanism so as to rotate continuously and automatically the said shaftscorres onding to the movement of the observed point (M), speed controlmeans 3, 1. 8 coacting with said speed mechanism for adiusting thelatter for an output speed (6) equal to the velocity (v) of the observedpoint (M) divided by the present range value (6), said control meansbeing controlled by the shaft 9 for registering the present range value(ei, a shaft 25 for-re isterin the present angle (1) between the line ofsight (IM) for said observed point (M) and the tangent of a path alongwhich the said observed point (M) moves, gear means connecting said lastmentioned shaft with the aforementioned system of shafts for rotatingthe said shaft 20 by the system of shafts, a second shaft 99 forregistering the present angle (K) between the plane of sight (MIT) forsaid observed point (M) and a horizontal line (MR) perpendicular to saidline of sight (IM), ear means connecting said latter shaft with theaforementioned system of shafts for rotating the said shaft 99 by the sstem of shafts: and a second group of means 5|. 58. 76 com rising oneelement 5! for altering the rate of chan e (a') of the azimuth angle(a), one element 58 for altering the rate of chan e (4)) of theelevation 5), and one element 15 for altering the rate of change ()8) ofthe logarithm (x) of the present range value (e), gear means andcontinuously variable resolvers 52, 51. 63, 18 connecting said'secondgroup of means with respective shafts of the first group of means toprovide for a change in the values of the rate of changes (11, )J),thereby permitting a variation of the course and speed of said observedpoint (M) so that the same corresponds to the course and speed of atarget to be observed and tracked.

2. An apparatus as described in claim 1, Wherein an axle 4 is connectedto said drive means i, 2 for rotation thereby with an angular velocityproportional to (e) the rotational movement of said axle 4 beingtransmitted to said azimuth shaft 3| over the said interconnectedresolvers and gears of the first group of means at the ratio i COS11.005 K cos (through 5, IO, 26, 29, 30 to 3|), at the ratio cos 1/ sinK to said elevation angle shaft 28 (through 5, [0, 2.6 to 28), at theratio sin y to 13 said shaft 9 for the loragithm x (through! to 9) atthe ratio cos w-cos K-tan to said shaft 99 for the angle K (through 5,I9, 25, 29, 39, 32, 98 to 99), and at the ratio cos 4: to said shaft 20for the angle v (through 5, "-19 to 29).

3. An apparatus as described in claim 1, wherein the aforesaidcontinuously variable resolvers 5, 25, 39 controlled through shafts I9,l5, I1, 29, 23, 21, I04, 52; 28, 35, 38 and gears II to l4, l5, l8, 19,2|, 22, 24, 25; I95, I05, I02, I03; 33, 34, 35, 31, and whereincontinuously variable resolvers and gearings are connected to theelement 5| of the second group of means for changing the rate of changea, when the said element is rotated through an adjustment angle Au, arearranged to transmit rotational movement at the ratio cos .sin K e.cos Iof said angle Ad to the said shaft 99 for the angle K (through 52, 53,51, 5|, 95, 91, and 98 to 99), to transmit rotational movement at theratio cos .cos K.Sil1 v of said angle Ad to the said shaft 20 for theangle 1 (through 52, 53, 51, 59, 55-59, 19-15, 54, 53, 11, 18, 85, I5-l9to 29), and to transmit rotational movement at the ratio cos -cos x-cosv of said angle Ad. to the said control means 3, 1, 8 of the outputspeed e (through 52, 53, 51, 59, 55-15, 54, 53, 41a, 48-59 to shaft ofscrew 8); and wherein the continuously variable gearings and gearsconnected to said element 58 for altering the rate of change qb, whensaid element is rotated through an adjustment angle no, are arranged totransmit rotational movement at the ratio COS K e'.cos v of said angle Ab to the said shaft 99 for the angle 1: (through 59, 51, 5|, 95, 91, 98to 99), to transmit rotational movement at the ratio sin 1:.Sill r ofsaid angle no to the said shaft 20 for the angle v (through 59, 51, 59,55-15, 54, 53, 11, 18, 85, 16-19 to 29), and to transmit rotationalmovement at the ratio sin x-cos v of said angle A' to the said controlmeans. 3, 1, 8 for the output speed 6' (through 59, 51, 59, 55-15, 54,53, 41a, 48, 49, 50 to shaft of screw 8); and wherein said continuouslyvariable gearings and gears connected to said element for altering therate of change A, when said element is rotated through an adjustmentangle AA, are arranged to transmit rotational movement at the ratio cosw I of said angle AA to the said shaft 29 of the angle 1 (through 55,53, 11, 18, 85, l5, l1, l8, I9 to 29), and to transmit rotationalmovement at the ratio sin y of said angle AA to said control means 3, 1,8 for the output speed e' (through 65, 53, 41a, 48, 49, 59 to shaft for8).

4. An apparatus as described in claim 3, wherein the said resolvers 5,25, 39 include a resolver 5 which is self-controlled and anotherresolver 25 which controls still another resolver 39.

5. An apparatus as described in claim 1, in combination with adisk-shaped element 39 rotated by said shaft 9 for the logarithm Arotates (through 49-44) with an angular velocity proportional to saidrate of change A, a rotatable element 45 driven by the said disk-shapedelement 39 and controlled by said drive means for the output speed c soas to maintain the distance between said rotatable element 45 and thecenter of said disk-shaped element 39 continuously proportional to thequantity e', and a shaft 41 rotated by said rotatable element 45 with anangular velocity proportional to the product 621', the rotationalmovement of said last-mentioned shaft 41 being transmitted (through48-50) to said drive means for said output speed s.

6. An apparatus as described in claim 1, in combination with a rotatableballistic cam 91 mounted for movement in rotary and axial direction,said cam being rotated by means of said shaft 29 for registering thepresent angle between the line of sight (IM) for said observed point (M)and the tangent of a path along which the said observed point (M) ismoved by means of the respective shafts and gears, said cam being movedin axial direction by said control means 3, 1, 8, a dog 93 engaging thesurface of said cam 81 for control of the dog position by theconfiguration of the cam surface, and a motion-creating means 94controlled in output speed by the position of said dog, the output speedof the said means 94 being transmitted to the shaft 99 for registeringthe present angle 1:) between the plane of sight (MIT) for said observedpoint (M) and a horizontal line (MR) perpendicularly to said line ofsight (IM) by means of the respective shafts and gears.

SVEN GUNNAR GERDlN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,751,649 Nieman Mar. 25, 19302,065,303 Chafee Dec. 22, 1936 2,385,952 Svoboda Oct. 2, 1945 cu Mull.

Certificate of Correction Patent No. 2,567,665 September 11, 1951 SVENGUNNAB GERDIN It is hereby certified that error appears in the printedspecification of the above numbered patent requiring correction asfollows:

Column 5, line 5, for that portion of the equation reedin g 1og." read109 3; column 10, line 25, for that portlon of the equation readmg A:read A-=;

and that the said Letters Patent should be read as corrected above, sothat the some may conform to the record of the case in the PatentOfiiee.

Signed and sealed this 27th day of May, A. D. 1952.

THOMAS F. MURPHY,

Assistant Oommissioner of Patenta.

